1. Field of the Invention
This invention relates to accessory devices and more particularly to accessory devices which are combined with microphones or telephones.
2. Description of the Prior Art
Numerous types of devices have been developed by the prior art for providing illumination during communication via a microphone or a telephone. Both integral and auxiliary bulbs have been combined with telephones for illuminating the dial of the telephone or a telephone number or note sheet. The auxiliary illumination devices included a battery which was separate and independent of the audio circuit of the telephone or microphone device. When the charge on the battery was depleted, the user would merely replace the battery with a new or recharged battery. In the integral illuminating devices, the illumination device received electrical power from either the audio circuit or a separate circuit connected to conventional household wiring.
An important application for a combined microphone and illuminating or other accessory device is the area of two-way radio transmitters. In general, the transmitter radio has a microphone audio circuit for receiving electrical signals produced by the microphone, which electrical signals modulate a radio frequency carrier wave. The transmitter radio also includes a transmitter activation circuit generally having a first and a second terminal with a potential established therebetween. A microphone key switch interconnects the first and second terminals to activate the transmitter radio upon closing the microphone key switch. In many transmitter radios, a relay type device is incorporated in the transmitter activating circuit to energize the radio frequency circuits within the transmitter radio when a given current level flows between the first and second terminals.
The present industrial standard for most transmitter radio equipment includes a three, four or five conductor jack disposed within the transmitter housing for receiving a multiple conductor plug connected to a microphone device. The first jack conductor is connected to the transmitter activating circuit, the second jack conductor is connected to a ground circuit, and the third jack conductor is connected to the microphone audio circuit. A microphone key switch comprising a first and a second switch interconnect the first and third plug conductor with the second plug conductor. Accordingly, upon closing the microphone key switch, the microphone audio circuit is concomitantly energized with the transmitter activating circuit thereby enabling the audio signals generated by the microphone to modulate the radio frequency carrier wave of the transmitter.
There is a need in the art for a combined microphone-illumination or another accessory device which is compatible for use with the aforementioned standard transmitter radio and which may be incorporated therein without interrupting the normal operation threof.
Therefore, it is an object of this invention to provide an apparatus which overcomes the aforementioned inadequacies of the prior art devices and provides an improvement which is a significant improvement to the advancement of the microphone and accessory art.
Another object of this invention is to provide a combined microphone and accessory device including a constant current circuit which extracts a current level less than the given current level required to activate the radio transmitter. This given current level may be used as a power supply for such electronic applications as recharging rechargeable batteries, timing and calculator circuits.
Another object of this invention is to provide a combined microphone and accessory device for operation with a transmitter radio including the accessory device mounted to the microphone housing and powered by a rechargeable battery. A recharging circuit is connected for recharging the battery from a potential normally used for activating the transmitter radio the recharging current flow is less than the given current level required to activate the transmitter radio.
Another object of this invention is to provide a combined microphone and accessory device for operation with a transmitter radio including a constant current generator for charging the rechargeable battery at a current level less than the current required to activate the transmitter radio.
Another object of this invention is to provide a combined microphone and accessory device for operation with a transmitter radio incorporated within a conventional microphone housing and using a standard multiple conductor plug receivable within a conventional transmitter without interferring with the normal operation of the transmitter radio.
Another object of this invention is to provide a combined microphone and accessory device for operation with a transmitter radio which may be manufactured as a microphone, a connecting cord and plug for operation with substantially all commercial two-way transmitter radio equipment.
Another object of this invention is to provide a combined microphone and accessory device with the accessory device comprising an illumination device and/or an electronic timing or calculating device for operation with a transmitter radio.
Other objects and a fuller understanding of this invention may be had by referring to the summary of the invention, the description and the claims, taken in conjunction with the accompanying drawings.